This invention relates to a mechanism for manually sharpening knife blades. The mechanism comprises a portable case that defines an upwardly facing trough adapted to removably receive a cutting stone. Upper wall areas of the case proximate to the trough flare outwardly and upwardly to form support surfaces for knife blades to be sharpened.
A knife blade is sharpened by resting the blade flatwise on one of the flaring support surfaces, with the cutting edge of the blade in contact with an upper flat face of the cutting stone (located within the trough). The knife is then moved back and forth parallel to the trough axis, such that the blade cutting edge experiences a grinding engagement with the stone surface.
The flaring support surfaces on the case are angled to the exposed surface of the stone at about twenty seven degrees. By keeping the blade in flatwise engagement with a support surface it is possible to form a precise cutting angle on the blade edge. The case is formed with two flaring support surfaces at each side edge of the cutting stone; the knife blade can be selectively (sequentially) engaged with the two surfaces to form a V-shaped cutting edge on the blade.
The mechanism is designed as a relatively low cost device for obtaining a relatively sharp precise cutting edge on a knife blade. The device can be used on a variety of different sized knife blades. In a preferred form of the invention the cutting stone and trough structure are designed so that the stone can be reoriented in the trough with different flat surfaces of the stone facing upwardly to serve as blade grinding surfaces. This feature somewhat increases the useful life of the mechanism. Also, it permits the stone to be formed with coarse and fine grinding surfaces, thereby permitting relatively dull knife blades to be sharpened in a minimum time period (by first using the coarse surface and then using the fine surface).